The present invention generally relates to an image forming apparatus, and more particularly to an image forming apparatus having a scanning function and a printing function, which apparatus can be used with a host computer.
Some conventional image forming apparatuses having both a scanning function and a printing function, such as a laser printer equipped with a scanner, a digital copy machine or a facsimile machine, are equipped with an interface by which the image forming apparatus can be connected to a host computer. The image forming apparatus is connected to the host computer via an interface such as an RS232C interface.
Under such a connected condition, a printer and a scanner in the image forming apparatus are independently controlled by the host computer. Namely, the printing function and the scanning function of the image forming apparatus are controlled by a command signal sent from the host computer. Additionally, the host computer may send image data to be printed out by the printer of the image forming apparatus as well as sending a command signal. Image data may be transferred from an optional apparatus, such as a hard disk apparatus or a floppy disk apparatus connected to the image forming apparatus in accordance with a command from the host computer.
However, since the host computer has many jobs other than controlling the image forming apparatus, when the host computer is performing other jobs, an operation speed of the image forming apparatus may become slow. Additionally, an executing speed of the host computer for jobs other than controlling of the image forming apparatus may also become slow.